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Re:KZ550 Power loss 30 Mar 2015 18:13 #665848

  • 650ed
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"#2 cylinder was wet"

Assuming you have the stock petcock it will be vacuum operated using a vacuum hose that connects the petcock to the #2 carb. Sometime when the diaphragm inside the petcock fails it permits fuel to be drawn through that vacuum hose into the #2 carb. If that happens, cylinder #2 can get too much fuel which could be the reason you found #2 to be wet. I suggest you temporarily remove the vacuum line from the petcock and #2 carb. Cap off both the ports on the petcock and on the carb. Then run the bike with the petcock in the Prime position. That will enable fuel to flow to the carbs but will eliminate the possibility of extra fuel being drawn into #2 through the vacuum line.

If the problem goes away when running like this you will need to rebuild or replace the petcock. While that vacuum line is removed be sure to turn the petcock to the Run position when the bike is parked with the engine off. Otherwise you could end up with a fuel overflow issue if a carb float valve sticks open. Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)

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Re:KZ550 Power loss 30 Mar 2015 19:47 #665871

  • SWest
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Sound advice.
Steve

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Re:KZ550 Power loss 31 Mar 2015 02:07 #665894

  • Patton
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GatlinM wrote:

Attachment ImageUploadedByTapatalk1427762056.821266.jpg not found


Each carb float was leveling the same.
. . .
12 volts at battery. At the coils power was at 10 volts . . .

Air filter seemed normal, slight smell of fuel.

Went through plenty of wires, again, assuring connections, replaced all fuses, and started up. Bike ran for a minute, then same old problem. . . .


The clear tube test entails attaching the clear tube to the carb drain function and not to the carb overflow function.
From the picture, it appears that the clear tube might be incorrectly attached to an overflow nipple.
Is there a separate drain screw?

Should be no loss in voltage between battery+ and primary terminals on the ignition coils.
In other words, the ignition coils are supposed to receive all the voltage being produced by the battery.

Such loss in voltage may result from corrosion in wiring connectors or within a switch or at the fuse connections. The following illustration indicates some places to check for lost voltage.





Would also inspect and confirm integrity of the ground connection where the negative battery cable attaches to the engine.

I also concur with Ed's suggestion about possible petcock malfunction.

And don't forget to check for possible contamination (dilution) of the crankcase oil with gasoline which may have intruded into the crankcase -- which can result in catastrophic engine failure.

Good Fortune! :)
1973 Z1
KZ900 LTD
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Last edit: by Patton.

Re:KZ550 Power loss 02 Apr 2015 22:37 #666348

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Thanks for keeping up with me on this.

Bike has decided to run fine over the last few days, though I've been checking over these suggestions, anyways.

Patton, the bowls on the carbs only have one drain screw, I accidentally flipped some bowls putting the carbs back together, so the screw is on the opposite side. On the inside, of the bowl they do have a stem rising up for overflow. I've always assumed the bottom screws released into the same overflow exit tubes.

Attachment ImageUploadedByTapatalk1428038092.882368.jpg not found



With the battery at 12 volts, I began checking the wiring at the points on diagram. Again, slight electric loss, as I was leaving electricity on.

The 20amp fuse has always run hot, since I've had the bike, the junctions on either side, also warm.

Attachment ImageUploadedByTapatalk1428038552.949702.jpg not found



Oddly, this little blue guy seemed to be an issue. Wiring into it, is the power from the starter switch. When I began checking flow, I was getting near full power at the connection just after the switch. The red wire cuts into power just before the split into the coils. The red wire runs down to the Dyna ignition. Pulling the red wire out was giving me the 11-12 volts all round, while measuring with it connected, was pulling a lot of these numbers down to 9-10volts.
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Re:KZ550 Power loss 03 Apr 2015 03:05 #666349

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GatlinM wrote: . . . bowls on the carbs only have one drain screw . . . On the inside, of the bowl they do have a stem rising up for overflow. I've always assumed the bottom screws released into the same overflow exit tubes . . . With the battery at 12 volts, I began checking the wiring at the points on diagram. Again, slight electric loss, as I was leaving electricity on . . .

Attachment ImageUploadedByTapatalk1428038552.949702.jpg not found



Oddly, this little blue guy seemed to be an issue . . . was getting near full power at the connection just after the switch. The red wire cuts into power just before the split into the coils. The red wire runs down to the Dyna ignition. Pulling the red wire out was giving me the 11-12 volts all round, while measuring with it connected, was pulling a lot of these numbers down to 9-10volts.


If the carbs at hand are designed so that loosening (not removing) the drain screw empties all fuel from the bowl, the clear tube test would be performed with a loosened drain screw.
The clear tube test relies on fuel being supplied from the drain function.
The clear tube test should not involve fuel being supplied from the overflow function.


The little blue guy (wire tap squeeze/snap "Scotchloc" connector) is likely supplying switched battery voltage to the Dyna-S electronic ignition.
The intermittent loss of combustion in #2 and #3 cylinders might result from a malfunction in the Dyna-S pick-up module that's located under the points cover in the 3 o'clock position. (The other Dyna-S pick-up module regulates firing for the #1 and #4 cylinders through the other ignition coil).

As to the voltage loss through the blue connector, am guessing there might be a shorted wire into or out of the Dyna-S pick-up module, or a malfunction within the module itself (perhaps heat-related?), or possibly just a loosely attached module that needs tightening.

Would also assure that the Dyna-S rotor is clean and that the pick-up modules are clean where the rotor's embedded magnet passes by the pick-up.

Good Fortune! :)
1973 Z1
KZ900 LTD

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Last edit: by Patton.

Re:KZ550 Power loss 28 May 2015 19:02 #674282

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Patton,
Thanks for the reply, it was unfortunate KZR was hacked during my time of need.

For short distance riding to work, this past month, the 550 has been fine. Although, days ago I tested a bit longer ride, and sure enough cylinders 2 & 3 dropped out.

I was able to find other threads with folks having the same issue with the Dyna S ignition. Coming back to KZR, your post confirmed the right module may be at fault. Dynaonline.com even has a troubleshooting document for the ignition.

www.powercommander.com/downloads/Support...Manuals/DynaSTSG.pdf

In following their tests, I found the right module (2/3) seems to be stuck, supplying full voltage, continuously.

I did get about 5 years on the Dyna S, which seems good compared to others lifetimes. I hope to purchase a repair soon, and get back on the road.

Thanks again for all the help, I'll update when I can get the fix in.

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Re:KZ550 Power loss 11 Jul 2015 15:02 #680423

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Update!

I ended up sending the Dyna in to have it tested. It was indeed a module failure for 2/3. As the ignition was a ways out of warranty, Dynatek was courteous enough to offer a brand new replacement for a fair price.

It's been a few weeks with the new ignition in place, and the bike has been running smoothly. I've always been a bit cautious about running the engine too hot, and it seems overheating has led to Dyna failures for other riders.

Thanks again, all, for advice and patience. See you on the road!

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Re:KZ550 Power loss 11 Jul 2015 19:31 #680455

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At your next chance, replace the blue "Suitcase" electrical connector, with solder and heatshrink tubing, as they have been proven to be unreliable. Moisture gets in, and corrosion sets up house there. lowering voltage and current to the ignition system.
1982 GPZ1100 B2
General Dynamics/Convair 1983-1993
GLCM BGM-109 Tomahawk, AGM-129A Advanced Cruise Missile (ACM)

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